U.S. Pat. Nos. 4,794,883 and 4,798,050 describe motor vehicle hydraulic systems having separate flow circuits for steering power assist and for a second accessory of the motor vehicle, e.g., a radiator cooling fan. A first of the two flow circuits includes a reservoir, a power steering pump connected on an upstream side to the reservoir through a first inlet conduit and on a downstream side to the reservoir through a first return conduit, a steering assist fluid motor, and a first control valve in the first return conduit for managing fluid flow between the first return conduit and each of a pair of working chambers of the steering assist fluid motor. A second one of the two flow circuits includes the aforesaid reservoir, a second pump connected on an upstream side to the reservoir through a second inlet conduit and on a downstream side to the reservoir through a second return conduit, a second fluid motor in the second return conduit for driving the radiator cooling fan, and a second control valve for managing fluid flow through the second fluid motor.